Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-09-24
2004-07-13
Davis, Zinna Northington (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C546S314000
Reexamination Certificate
active
06762303
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for producing a pyridine compound that is useful for photographic additives, sensitizing dyes, pharmaceuticals, organic EL materials, liquid crystal materials, nonlinear optical materials, and so on, or for synthetic intermediates of these materials.
BACKGROUND OF THE INVENTION
Examples of methods for synthesizing pyridine compounds by oxidation of a dihydropyridine compound include an oxidation method using oxygen (as described, for example, in Bull. Chem. Soc. Jpn., 57(7), 1994-1999 (1984); Tetrahedron Lett., 23 (4), 429-432 (1982); and Synth. Commun., 21 (3), 401-406 (1991)); an oxidation method using sulfur (as described, for example, in Chem. Pharm. Bull., 38 (1), 45-48 (1990); J. Org. Chem., 53 (18), 4223-4227 (1988); and JP-A-6-172347 (“JP-A” means unexamined published Japanese patent application)); an oxidation method using o-chloranil (as described, for example, in J. Org. Chem., 48 (24), 4597-4605 (1983); and Heterocycles, 22 (2), 339-344 (1984); and an oxidation method using DDQ (as described, for example, in Tetrahedron, 48 (27), 5647-5656 (1992); and Heterocycles, 45 (3), 434-438 (1997)). However, these methods had disadvantages that the reaction required a long time or high temperature, and moreover, post-treatment, such as removal of a residue, also required much time. Accordingly, it is difficult to say that these methods were suitable for industrial production. Further, these methods were also unsatisfactory as industrial production methods from the viewpoints of cost and environment.
Further, purification techniques, such as chromatography and distillation, have been employed to yield a pyridine compound of high purity. However, the chromatography requires so much chromato-carrier and elution solvent that it is not suitable for industrial production. The distillation also has the problem that it is difficult to purify a pyridine compound having a low melting point or a high boiling point.
SUMMARY OF THE INVENTION
The present invention is a method for producing a pyridine compound represented by formula (II), which comprises oxidizing a dihydropyridine compound represented by formula (I), in the presence of (i) at least one acid and at least one compound selected from the group consisting of nitrous acid and a nitrite, or (ii) at least one base and a hydrogen peroxide solution:
wherein each of R
1
to R
5
independently represents a hydrogen atom, or a substituent; L represents an alkyl group, an alkoxy group, an aryl group, or an aryloxy group, each of which may have a substituent:
wherein each of R
1
to R
5
has the same meanings as those of formula (I).
Further, the present invention is a method for producing the pyridine compound represented by formula (II), which comprises subjecting a crude salt product formed from said pyridine compound and an acid to an active carbon treatment in a solvent containing water, thereby purifying the pyridine compound.
Other and further features and advantages of the invention will appear more fully from the following description.
DETAILED DESCRIPTION OF THE INVENTION
The present invention resides in a producing method of a pyridine compound described below.
(1) A method for producing a pyridine compound represented by formula (II), comprising oxidizing a dihydropyridine compound represented by formula (I), (i) in the presence of at least one acid (in the present specification and the claims, this “acid” mentioned herein means an acid other than nitrous acid and nitrite), and at least one compound selected from the group consisting of nitrous acid and a nitrite, or (ii) in the presence of at least one base and a hydrogen peroxide solution:
wherein each of R
1
to R
5
independently represents a hydrogen atom, or a substituent; L represents an alkyl group, an alkoxy group, an aryl group, or an aryloxy group, each of which may have a substituent:
wherein each of R
1
to R
5
has the same meanings as those of formula (I).
(2) The method for producing a pyridine compound according to item (1), wherein the reaction is conducted in the presence of at least one acid and at least one compound selected from the group consisting of nitrous acid and a nitrite.
(3) The method for producing a pyridine compound according to item (2), wherein said acid is a carboxylic acid.
(4) The method for producing a pyridine compound according to items (2) or (3), wherein said nitrite is an alkali metal nitrite or an alkaline earth metal nitrite.
(5) The method for producing a pyridine compound according to any one of items (2) to (4), wherein each of R
1
, R
2
, R
4
, and R
5
represents a hydrogen atom, and R
3
represents an aryl group in formula (I) and formula (II) respectively.
(6) A method for producing a pyridine compound represented by formula (II) described below, comprising subjecting a crude salt product formed from said pyridine compound and an acid to an active carbon treatment in a solvent containing water, thereby purifying the pyridine compound:
wherein each of R
1
to R
5
independently represents a hydrogen atom, or a substituent.
(7) The method for producing a pyridine compound according to item (6), wherein each of R
1
, R
2
, R
4
, and R
5
represents a hydrogen atom, and R
3
represents an aryl group in formula (II).
(8) The method for producing a pyridine compound according to item (1), wherein the reaction is conducted in the presence of at least one base and a hydrogen peroxide solution.
(9) The method for producing a pyridine compound according to item (8), wherein said base is an inorganic base, or an alkoxide of an alkali metal or alkaline earth metal.
(10) The method for producing a pyridine compound according to the items (8) or (9), wherein each of R
1
, R
2
, R
4
and R
5
in formulae (I) and (II) is a hydrogen atom.
Next, the production method of the present invention will be explained in detail.
The dihydropyridine compound represented by formula (I), which is used in the present invention, and the pyridine compound represented by formula (II), which is produced by the method of the present invention, are explained.
In formulae (I) and (II), each of R
1
, R
2
, R
3
, R
4
, and R
5
independently represents a hydrogen atom, or a substituent. Examples of the substituent include a halogen atom (e.g., fluorine, chlorine, bromine, iodine), an alkyl group (e.g., methyl, ethyl), an aryl group (e.g., phenyl, naphthyl), an alkenyl group (e.g., vinyl), a cyano group, a formyl group, a carboxyl group, an alkoxycarbonyl group (e.g., methoxycarbonyl), an aryloxycarbonyl group (e.g., phenoxycarbonyl), a substituted or unsubstituted carbamoyl group (e.g., carbamoyl, N-phenylcarbamoyl, N,N-dimethylcarbamoyl), an alkyl carbonyl group (e.g., acetyl), an arylcarbonyl group (e.g., benzoyl), a nitro group, a substituted or unsubstituted amino group (e.g., amino, dimethyl amino, anilino), an acylamino group (e.g., acetamido, ethoxycarbonylamino), a sulfonamido group (e.g., methanesulfonamido), an imido group (e.g., succinimido, phthalimido), an imino group (e.g., benzylideneamino), a hydroxyl group, an alkoxy group (e.g., methoxy), an aryloxy group (e.g., phenoxy), an acyloxy group (e.g., acetoxy), an alkylsulfonyloxy group (e.g., methane sulfonyloxy), an arylsulfonyloxy group (e.g., benzenesulfonyloxy), a sulfo group, a substituted or unsubstituted sulfamoyl group (e.g., sulfamoyl, N-phenylsulfamoyl), an alkylthio group (e.g., methylthio), an arylthio group (e.g., phenylthio), an alkylsulfonyl group (e.g., methanesulfonyl), an arylsulfonyl group (e.g., benzenesulfonyl), a silyl group (e.g., dimethylphenylsilyl, triphenylsilyl), a phosphoryl group (e.g., dimethoxyphosphoryl), a heterocyclic group (e.g., 3- to 10-membered saturated or unsaturated heterocyclic group containing at least one of N, O and S atoms, in which sail ring may be a single ring or a condensed ring formed by condensation with another ring; such heterocyclic group is preferably a 5- or 6-membered heterocyclic group, more preferably a 5-membered heterocyclic group containing a nitrogen atom). Besides
Suzuki Ryo
Yamakawa Katsuyoshi
LandOfFree
Method for producing pyridine compounds does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing pyridine compounds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing pyridine compounds will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3225099